spillman



Wa I. SPILLIVIAN.`

PERPETUAL CALENDAR.

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` PERPETUAL CALENDAR.

APPLICATION man MAHB, 1920. f

1 ,374,532. Patented Apr. 512, 19'121.

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UNITED STATES lILLIA'lVI J. SPILLMAN, WASHINGTON, DISTRICT OF-COLUMBIA. v

PERPETUAL CALENDAR.

terasse.

Specification of Letters Patent. Patented. Api'. 1,2, 1921.

Application filed May 18, 1920. Serial No. 382,262.

To all whom t may concern Be it known that l, WILLIAM JASPAR SHLLMAN, av citizen of the United States, residing at Washington, District of Columbia, have invented certain new improvements in Perpetual Calendars, ofwhich the following is a specification.

This invention relates to calendars of the type generally termed perpetual calendars, and has as one oi its objects the provision of a calendar by which the day of the week of any desired date within a definite period of years may be readily and directly determined. Further objects are the provision oi a calendar of this type which will facilitate the determination of the day of the week or any date whether of the Gregorian (new style) or Julian (old style) calendar, and the provisionvof such an arrangement of the various parts of the calendar as will facilitate and simplify its use.

Various embodiments of my invention are illustrated in the accompanying drawings and i'urther objects of the invention and features of novelty will be apparent Jfrom the following description when taken 1n connection with such drawings, in which:

Figure 1 and Fig. 2 show the various charts or tables which comprise one embodiment of my invention; and

Fig. 3 shows a modied arrangement in.

which my invention may be employed.

In each of the modifications a table of numbers indicating years is employed, such numbers being arranged to correspondto a set o symbols such as the numerals 1 to 7 or theletters A to G; and a table of month calendars is provided, each having one of one direction with the four columns of cen# tury numbers and in another direction with the seven lines of the year-of-the-century numbers. The numbers indicating leap years may be repeated as shown, or may be The table f indicated in only one Vor in both spaces, as desired, and it will be evident that for any common year the corresponding symbol may be found in the same columnas its century number and on the same line as its year-oithe-century number. For leap years therewill be two symbols, the first ot' which is to be used tor tliemonths. oft'. January and February in such years, and the second of which applies to the other months ofsuch years, for a reason which will be apparent.

A table 12 is provided which comprises a plurality of month calendar tables, there being seven monthA calendary tables for each month of the yearV and each beginning on a different day of the week and having as marginal indicia the seven symbols used in part 11C of the table 11. Thenumerals of the month calendar tables are arrangedqunder indicia of the days of the week, and it will be understood that the number of numerals used in the month calendar for each month will be the sameas that of the number of days in such month, the numerals 1 to, 29 being used for February. I have shown the symbolsV of the table 12- as arranged n a marginal part 12b, and spaced from the body of the table 12a to permit the arrangementof the part 120- of the presently table wherein certain year numbers may be arranged as shown. These numbers preferably indicate the years immediately adjacent the time at which they calendar is used and are arranged iii groups of seven spaces with two spaces for leap' years as in the pai't 11b of the table 11. Y

To find the calendar applicable for a given month, for a year from 1917 to 1944, inclusive, it is only necessary to find in the part 12c of the table 12 for the given month. the line on which the-year number occurs and follow such line to the right to find any given date in the month. Thecolumn in which the date occurs willy be headed by the indicia of the day ofthe week on which such date occurs. lf the date is in a leap year,

the first line is used for dates in January Viio symbol occurs for the vgiven month.r Such A line Will have the numbers of the days of the month arranged under the indicia of the days of the Week on Which they fall.

In order to adapt the calendar for the determination of ldates in the Julian calendar, called old style calendar, I have shown the table 11 as having a portion 11l in part ofV Which the numerals indicating the first twenty centuries are arranged in seven columns, and in another part of which the symbols are arranged to correspond 1n one direction With such columns and in another direction Withthe lines of the numerals indicating the years of a century in the part 11b of the table. The symbols in the table 11d for vany given year may be found in the same manner as those for dates in the Gregorian calendar and maybe used in the same Way by referring to the table 12 to find the month calendar applicable for a given month.

The principle involved is that, since a common year has one day in addition to the fifty-two Weeks While a leap year has tWo days'in addition to the fifty-two Weeks, a common year or the months of January and February of leap year, or the months of March to December of a leap year each constitute what may be termed a calendar period, and the .effect of each will be to postpone by one day the day of the Weel-z on which a given date will fall. If a series of successive calendar periods Were divided into groups of seven and numbered in order, in all periods of the same number any given month Would begin on the same day of the Week. Hence by arranging the' numerals indicating the years successively ingroups of seven spaces with tvvo spaces for leap years, in those years Whose numbers occur in the same position in their groups the same month calendars will be applicable for the variousrmonths. It Will also be apparent that since only every fourth centennial year in the Gregorian calendar is a leap year, dates which differ by exactly four centuries Would fall on the same day of the Week, so that symbols which correspond to a given year in the fifteenth century Would also correspond with the same year in the nineteenth century. In the Julian calendar every fourth year is. a leap year and d'ates Which differ by exactly seven centuries Would fall on the same day ofthe vveek.- v

The embodiment of my invention shown in Fig. 3 comprises seven month calendar tables V13, each beginning on a different day of the Week and designated by one of the symbols A to G, the numerals 1 to 31 being arranged under indiciaiof the days of the Week. A second part of the calendar cony sists of a table 13b of numbers indicating spaces With tvvo spaces for leap years. 'The table 13b is provided at the margin with the numerals 1 to 7 Which indicate the position of the year numbers in their groups.

An index table 14 is provided in which the symbols A to G of the month calendar tables are arranged in groups of seven under indicia 0f the months of the year, the symbols in each group being numbered consecutively from 1 to 7 to indicate their position in the group.

To find the calendar applicable for a given date of the Gregorian calendar, the number ofthe year is found in the table 13b and the marginal number 1 to 7 of the line is noted. Under the column in the table 1li Which is headed by the indicia of the given month, that symbol A to G is found which corresponds to the marginal number, and such symbol is that of the month calendar table 13 which is applicable for the given month and year. For dates in leap years the marginal number corresponding to the first occurrence of the year number is used for dates in January and February and the number corresponding to the second occurrence for dates in the other months. rllhe table lbpreferably covers a period of four centuries, and it Will be apparent that for any date outside of the period covered such multiple of 400 may be added to or subtracted from the year as Will bring it Within the table.

To provide for the use of the calendar shown in Fig. 3 for dates of the old style or Julian calendar, a table lfmay be provided in which numerals O to 27 are arranged in groups of seven spaces, with tWo spaces for numerals divisible by 4 and having marginal indicia 1 to 7, as in the table 13b. Since everyrfourth year in the Julian calendar is a leap year, twenty-eight years .constitute a solar cycle, at the end of which the days of the month again fall on the same days of the Week, so that a table for twenty-eight years will suffice. The procedure in using the table is the same as that for the dates of the Gregorian calendar, such even multiple of 28 being added to or subtracted from the year number as Will bring it Within the limits of the table. The series could run from 1910 to 1937, inclusive, but it is preferable to use the numerals O to 27, as-shovvn, so that the number indicating a year may be divided by 28 and the remainder found in the table 15 as if it were the number of the year.

1t will be .understood that various changes may be made in either of the embodiments of my invention shown, especially as tothe arrangement of the parts. For instance, the arrangement as to columns and lines maybe interchanged, other characteristics than the symbols shown herein or characteristic colors may be employed in the index table t0 correspond to similar characteristics or colors designating the month calendar tables,

. and various other changes' may be made as do those numbers in their groups of seven spaces4 which indicate years 1n which said month calendar is applicable.

2. A calendar comprising a plurality of month calendar tables, each having one of seven symbols, a table of numbers indicat-V ing yearsarranged consecutively in groups of seven spaces With tvvo spaces for the numbers indicating leap years, and a table having the seven month calendar symbols so arranged therein that the position of any given symbol in the table corresponds with the position of those numbers in the groups of seven spaces of the year indicating table which indicate years for Which the month calendar table having such symbol is applicable.

3. A calendar comprising a table of numbers indicating years-ot-a--century arranged in groups of seven spaces With two spaces for leap years, a table of numbers indicating centuries, a plurality of month calendars having distinguishing characteristics, and a table having the month calendar designating characteristics arranged therein to register in one direction With certain of the century indicating numbers and in another direction With certainof the year-of-a-century indicating numbers, the characteristics corresponding to given years being those of month calendars applicable for such years.

4. A calendar comprising a table having the last tivo digits of the year numbers arranged therein in groups of seven spaces with tWo spaces for numbers indicating leap years, a table having the century digits of year numbers arranged therein in groups of four spaces, a table having seven symbols arranged therein so that each registers in one direction with certain of the century digits and in another direction With certain of the last tvvo digits to indicate certain years, and a table of month calendars designated by said symbols.

5. A calendar comprising a table of numbers indicating years arranged in groups of seven spaces With tvvo spaces for leap years,

Va plurality of month calendar tables each having one of seven distinguishing character1st1cs,'and a table having said characteristics arranged therein to correspond with the' spaces in the table of year indicating numbers, the characteristics corresponding to given years being those of the month calendar tables applicable for said years for all years except leap years, and the characteristics corresponding With the first space of leap year numbers being those for the month calendars for January and February in said leap years and those corresponding With the second space of leap year numbers being those for the month calendars for the other months in said leap years.

In testimony whereof I have hereunto set my hand. n

W. J. SPILLMAN. 

